Platte River

Assessing Sandhill Crane Roosting Distribution

Each spring approximately 500,000 sandhill cranes and some endangered whooping cranes use the Central Platte River Valley in Nebraska as a staging habitat during their migration north to breeding and nesting grounds in Canada, Alaska, and the Siberian Arctic. Over the last century changes in the flow of the river have altered the river channels and the distribution of roost sites. USGS researchers determined a direct linkage between crane roosting habitat and river flows in the Platte. The results are useful for estimating crane populations and for providing resource managers with techniques to understand crane habitats.

[Histogram showing the ranges of depths and velocities used by roosting cranes in the Rowe Sanctuary study reach.]

In the reach of the Platte River near the Rowe Sanctuary, crane roost maps were defined from infrared video and then overlain on results from a flow model to identify the ranges in depth and velocity preferred by roosting cranes. Cranes generally prefer to roost in water depths less than 0.40 meters with velocities less than 0.70 meters per second. By examining these results at several stream flows, it was determined that the largest amount of available roosting habitat occurs at the Rowe Sanctuary when the streamflow in this channel is about 37 cubic meters per second. The study described shows how remote sensing, hydraulic modeling, and habitat assessments can be used to develop scientific tools for evaluating the efficacy of management actions.